Interplay of disorder and spin-fluctuation scattering

The low-temperature resistivity of many disordered paramagnetic materials often shows a $T^{\frac{3}{2}}$ rather than a $T^2$ dependence due to spin-fluctuation-scattering resistivity. The coefficient of the $T^{\frac{3}{2}}$ term often correlates with the magnitude of the residual resistivity as the amount of disorder is varied. We present a model calculation that exhibits such behavior. In the absence of disorder the spin-fluctuation drag suppresses the spin-fluctuation $T^2$ term in the resistivity. Disorder produces a finite residual resistivity and also produces a finite spin-fluctuation-scattering rate.